From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.4 required=3.0 tests=BUG6152_INVALID_DATE_TZ_ABSURD,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,INVALID_DATE_TZ_ABSURD,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 36708C5DF62 for ; Wed, 6 Nov 2019 10:19:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EDEC720869 for ; Wed, 6 Nov 2019 10:19:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1573035557; bh=TbCi1v0EBWWikEEGm5oxQHJ2Q6Bv5jfqqcOcNkFUMDk=; h=To:Subject:Date:From:Cc:In-Reply-To:References:List-ID:From; b=hSscfNWisRPAlMTYqsLlxHrKzAONH++hsqOwhVCXjSsCHqmt8X9iOWtG4FJJ23mDF yO1SkHz8NKQHCSen67DVctePjMdmJsPY4lkjhULOxVX+zyXrJFu3SpE5qD0TXbg4AG a0ONp8bkfN/SxQvM/zzrI2VlWuSDJwpR9B9kREIM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727257AbfKFKTQ (ORCPT ); Wed, 6 Nov 2019 05:19:16 -0500 Received: from inca-roads.misterjones.org ([213.251.177.50]:51332 "EHLO inca-roads.misterjones.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726143AbfKFKTQ (ORCPT ); Wed, 6 Nov 2019 05:19:16 -0500 Received: from www-data by cheepnis.misterjones.org with local (Exim 4.80) (envelope-from ) id 1iSIP7-0007q5-Ff; Wed, 06 Nov 2019 11:19:09 +0100 To: Michael Kelley Subject: Re: [PATCH v5 2/8] arm64: hyperv: Add hypercall and register access functions X-PHP-Originating-Script: 0:main.inc MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 06 Nov 2019 11:28:30 +0109 From: Marc Zyngier Cc: , , , , , , , , , , vkuznets , , , KY Srinivasan , Sunil Muthuswamy , "boqun.feng" In-Reply-To: <1570129355-16005-3-git-send-email-mikelley@microsoft.com> References: <1570129355-16005-1-git-send-email-mikelley@microsoft.com> <1570129355-16005-3-git-send-email-mikelley@microsoft.com> Message-ID: <8cdc86e5bcf861c74069e0d349910c94@www.loen.fr> X-Sender: maz@kernel.org User-Agent: Roundcube Webmail/0.7.2 X-SA-Exim-Connect-IP: X-SA-Exim-Rcpt-To: mikelley@microsoft.com, will@kernel.org, catalin.marinas@arm.com, mark.rutland@arm.com, linux-arm-kernel@lists.infradead.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-hyperv@vger.kernel.org, devel@linuxdriverproject.org, olaf@aepfle.de, apw@canonical.com, vkuznets@redhat.com, jasowang@redhat.com, marcelo.cerri@canonical.com, kys@microsoft.com, sunilmut@microsoft.com, boqun.feng@gmail.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on cheepnis.misterjones.org); SAEximRunCond expanded to false Sender: linux-hyperv-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hyperv@vger.kernel.org On 2019-10-03 20:12, Michael Kelley wrote: > Add ARM64-specific code to make Hyper-V hypercalls and to > access virtual processor synthetic registers via hypercalls. > Hypercalls use a Hyper-V specific calling sequence with a non-zero > immediate value per Section 2.9 of the SMC Calling Convention > spec. I find this "following the spec by actively sidestepping it" counter productive. You (or rather the Hyper-V people) are reinventing the wheel (of the slightly square variety) instead of using the standard that the whole of the ARM ecosystem seems happy to take advantage of. I wonder what is the rational for this. If something doesn't quite work for Hyper-V, I think we'd all like to know. Thanks, M. -- Jazz is not dead. It just smells funny...